This invention relates to a connector used in building construction, and in particular to a structural hanger for suspending a held framing member from a holding framing member in a building.
Hangers typically have a stirrup-shaped portion for receiving an end portion of a held framing member, such as a joist, a top flange for connecting the hanger to the support or holding member, such as a truss or a purling, and a back member that connects the stirrup portion to the top flange.
The stirrup portion generally comprises a seat member which the held framing member rests upon, and first and second opposite side members that stabilize the held framing member. The first and second opposite side members receive the end portion of the held framing member between them. The first and second opposite side members are generally formed with a plurality of openings for allowing the hanger to be nailed or otherwise attached to the held framing member. This further stabilizes the held framing member and provides uplift resistance. For an example of a hanger with a rather unique stirrup portion see U.S. Pat. No. 4,890,436, granted to Karen W. Colonias for a Multiple Wood Truss Connection.
The stirrup portion of the typical hanger is not the only means for supporting the held member taught by the prior art. For example, some hangers eliminate the seat member. They support the held framing member by means of fasteners or bolts received by one or more side member. In these situations the bolts or fasteners provide both bearing support and uplift resistance to the held framing member. For an example of such a hanger see U.S. Pat. No. 4,893,961 granted to Kevin B. O'Sullivan and Arthur L. Troutner for a Joist Hanger.
Still other hangers vary from the typical hanger form by eliminating the top flange which connects the hanger to the holding member. See U.S. Pat. No. 4,717,279 granted to Alfred D. Commins on Jan. 5, 1988 for a Bucket Hanger. This is especially true of hangers designed for connecting two plated trusses together. See, for example, U.S. Pat. No. 5,341,619 granted to Brian D. Dunagan and Alfred D. Commins on Aug. 30, 1994 for a Truss Girder Hanger Connection, and U.S. Pat. No. 4,890,436 granted to Karen W. Colonias on Jan. 2, 1990 for a Multiple Wood Truss Connection. These hangers are generally attached to the vertical web member of the carrying truss near the bottom of the truss. Because of their location near the bottom of the vertical web member, an elongated back member would be required to provide a top flange that could hook over the top of the carrying truss.
The hanger of the present invention differs from the prior art by providing an improvement to the connection between the hanger and the carrying or holding member. The hanger of the present invention differs from the prior art, first, by providing a connection flange that does not wrap over the top of the carrying or holding member, and, second, by allowing the fasteners that make the connection to the holding member to be in double shear with the hanger.
When the carrying member is composed of multiple plies, such as in various nail-plate trusses, and the double-shear configuration is used, the present invention provides improved distribution of the load to the plies in the carrying member. This is because the hanger introduces the load to the fasteners inserted through the carrying member from two sides of the carrying member. This uniform distribution of the load makes it easier to design multiple-ply trusses so that the plies act as one member.